package com.reservoir.gateway.handler;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.reservoir.core.entity.RestMsg;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.web.reactive.error.ErrorWebExceptionHandler;
import org.springframework.cloud.gateway.support.NotFoundException;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.annotation.Order;
import org.springframework.core.io.buffer.DataBufferFactory;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.web.server.ResponseStatusException;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

/**
 * 网关统一异常处理
 *
 * @author ruoyi
 */
@Order(-1)
@Slf4j
@Configuration
@RequiredArgsConstructor
public class GatewayExceptionHandler implements ErrorWebExceptionHandler {

    private  final ObjectMapper objectMapper;

    @Override
    public Mono<Void> handle(ServerWebExchange exchange, Throwable ex) {

        ServerHttpResponse response = exchange.getResponse();
        if (exchange.getResponse().isCommitted()) {
            return Mono.error(ex);
        }

        String msg;
        if (ex instanceof NotFoundException) {
            msg = "服务未找到";
        } else if (ex instanceof ResponseStatusException) {
            ResponseStatusException responseStatusException = (ResponseStatusException) ex;
            msg = responseStatusException.getMessage();
        } else {
            msg = "内部服务器错误";
        }

        log.error("[网关异常处理]请求路径:{},异常信息:{}", exchange.getRequest().getPath(), ex.getMessage());

        return response.writeWith(Mono.fromSupplier(()->{
            DataBufferFactory bufferFactory = response.bufferFactory();
            try {
                return bufferFactory.wrap(objectMapper.writeValueAsBytes(RestMsg.fail(ex.getMessage())));
            }catch (JsonProcessingException e){
                log.warn("Error writing response", ex);
                return bufferFactory.wrap(new byte[0]);
            }
        }));
    }
}